Magnetic field detection device

ABSTRACT

A magnetic field detection device of an embodiment of the disclosure includes: a first magnetic field detection element having a first resistance value increasing upon application of a first magnetic field in a first direction and decreasing upon application of a second magnetic field in a second direction; and a second magnetic field detection element having a second resistance value decreasing upon application of the first magnetic field and increasing upon application of the second magnetic field. The first and second magnetic field detection elements each include first and second magneto-resistive effect films coupled in series. The first magneto-resistive effect film has a first major-axis direction inclined at a first inclination angle relative to the first direction. The second magneto-resistive effect film has a second major-axis direction inclined at a second inclination angle relative to the first direction. The magnetic field detection device satisfies conditional expressions (1) and (2).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/414,870, filed May 17, 2019, now U.S. Pat. No. 11,002,803, thecontents of which are incorporation herein by reference.

This application claims the benefit of Japanese Priority PatentApplication No. 2018-110081 filed on Jun. 8, 2018, the entire contentsof which are incorporated herein by reference.

BACKGROUND

The disclosure relates to a magnetic field detection device providedwith a magnetic field detection element.

Up to now, there have been proposed several magnetic field detectiondevices each using a magneto-resistive effect element. For example,Japanese Unexamined Patent Application Publication No. 2016-1118discloses a magnetic field detection device in which a direction of acenterline of a conductor along a current-flowing direction is differentfrom a direction of a centerline of a magneto-resistive effect elementalong a longitudinal direction.

SUMMARY

A magnetic field detection device according to one embodiment of thedisclosure includes: a first magnetic field detection element having afirst resistance value that increases upon application of a firstmagnetic field in a first direction and decreases upon application of asecond magnetic field in a second direction opposite to the firstdirection; and a second magnetic field detection element having a secondresistance value that decreases upon the application of the firstmagnetic field and increases upon the application of the second magneticfield. The first magnetic field detection element and the secondmagnetic field detection element each include a first magneto-resistiveeffect film and a second magneto-resistive effect film that are coupledin series. The first magneto-resistive effect film has a firstmajor-axis direction inclined at a first inclination angle relative tothe first direction. The second magneto-resistive effect film has asecond major-axis direction inclined at a second inclination anglerelative to the first direction. Further, the following conditionalexpressions (1) and (2) are satisfied:0°<θ1<90°  (1)−90°<θ2<0°  (2)

where θ1 denotes the first inclination angle relative to the firstdirection, and θ2 denotes the second inclination angle relative to thefirst direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thedisclosure.

FIG. 1 is a perspective view of an overall configuration example of amagnetic field detection device according to one embodiment of thedisclosure.

FIG. 2A is a plan view of a planar configuration of a main part of themagnetic field detection device illustrated in FIG. 1 .

FIG. 2B is a plan view of another planar configuration of the main partof the magnetic field detection device illustrated in FIG. 1 .

FIG. 3A is a characteristic diagram illustrating a relation between areversed magnetic field of a magnetization free layer of amagneto-resistive effect film illustrated in FIGS. 2A and 2B and aninclination angle of the magneto-resistive effect film.

FIG. 3B is a characteristic diagram illustrating a relation between anormalized output relative to a signal magnetic field in themagneto-resistive effect film illustrated in FIGS. 2A and 2B and theinclination angle of the magneto-resistive effect film.

FIG. 4 is a circuit diagram of the magnetic field detection deviceillustrated in FIG. 1 .

FIG. 5A is an exploded perspective view of a stacked structure of afirst magneto-resistive effect film included in a first magnetic fielddetection element illustrated in FIG. 1 .

FIG. 5B is an exploded perspective view of a stacked structure of asecond magneto-resistive effect film included in the first magneticfield detection element illustrated in FIG. 1 .

FIG. 5C is an exploded perspective view of a stacked structure of athird magneto-resistive effect film included in a second magnetic fielddetection element illustrated in FIG. 1 .

FIG. 5D is an exploded perspective view of a stacked structure of afourth magneto-resistive effect film included in the second magneticfield detection element illustrated in FIG. 1 .

FIG. 6A is an exploded perspective view of another stacked structure ofthe first magneto-resistive effect film included in the first magneticfield detection element illustrated in FIG. 1 .

FIG. 6B is an exploded perspective view of another stacked structure ofthe second magneto-resistive effect film included in the first magneticfield detection element illustrated in FIG. 1 .

FIG. 6C is an exploded perspective view of another stacked structure ofthe third magneto-resistive effect film included in the second magneticfield detection element illustrated in FIG. 1 .

FIG. 6D is an exploded perspective view of another stacked structure ofthe fourth magneto-resistive effect film included in the second magneticfield detection element illustrated in FIG. 1 .

FIG. 7A is a schematic plan view of a set operation in the magneticfield detection device illustrated in FIG. 1 .

FIG. 7B is a schematic cross-sectional view of the set operation in themagnetic field detection device illustrated in FIG. 1 .

FIG. 8A is a schematic plan view of a reset operation in the magneticfield detection device illustrated in FIG. 1 .

FIG. 8B is a schematic cross-sectional view of the reset operation inthe magnetic field detection device illustrated in FIG. 1 .

FIG. 9A is a characteristic diagram illustrating dispersion of offsetcurrent values in a magnetic field detection device according to aworking example.

FIG. 9B is a characteristic diagram illustrating dispersion of offsetcurrent values in a magnetic field detection device according to areference example.

FIG. 10A is a plan view of a configuration of a main part of a magneticfield detection device according to a first modification example of thedisclosure.

FIG. 10B is a plan view of a configuration of a main part of a magneticfield detection device according to a second modification example of thedisclosure.

FIG. 11 is a plan view of a configuration of a main part of a magneticfield detection device according to a third modification example of thedisclosure.

FIG. 12A is a plan view of a configuration of a main part of a magneticfield detection device according to a fourth modification example of thedisclosure.

FIG. 12B is a plan view of another configuration of the main part of themagnetic field detection device according to the fourth modificationexample of the disclosure.

FIG. 13 is a plan view of a configuration of a main part of the magneticfield detection device according to the reference example.

DETAILED DESCRIPTION

Some embodiments of the disclosure are described below in detail withreference to the accompanying drawings.

Incidentally, a magnetic field detection device has been requested tohave further improved detection accuracy.

It is desirable to provide a magnetic field detection device that makesit possible to exhibit high detection accuracy.

It is to be noted that the following description is directed toillustrative examples of the technology and not to be construed aslimiting to the technology. Factors including, without limitation,numerical values, shapes, materials, components, positions of thecomponents, and how the components are coupled to each other areillustrative only and not to be construed as limiting to the technology.Further, elements in the following example embodiments which are notrecited in a most-generic independent claim of the technology areoptional and may be provided on an as-needed basis. The drawings areschematic and are not intended to be drawn to scale. It is to be notedthat the like elements are denoted with the same reference numerals, andany redundant description thereof will not be described in detail. It isto be noted that the description is given in the following order.

1. Example Embodiment

An example of a magnetic field detection device including a bridgecircuit that includes four magnetic field detection elements.

2. Modification Examples 1. Example Embodiment

[Configuration of Magnetic Field Detection Device 10]

First, description is given, with reference to FIGS. 1 to 4 , of aconfiguration of a magnetic field detection device 10 according to oneexample embodiment of the disclosure. FIG. 1 is a perspective view of anoverall configuration example of the magnetic field detection device 10.FIGS. 2A and 2B are each a schematic plan view of a planar configurationof a main part of the magnetic field detection device 10. FIG. 3A is acharacteristic diagram illustrating a relation between a reversedmagnetic field in a ±Y direction of a magnetization free layer of amagneto-resistive effect film illustrated in FIGS. 2A and 2B and aninclination angle of the magneto-resistive effect film. FIG. 3B is acharacteristic diagram illustrating a relation between a normalizedoutput relative to a signal magnetic field in the magneto-resistiveeffect film illustrated in FIGS. 2A and 2B and the inclination angle ofthe magneto-resistive effect film. FIG. 4 is a circuit diagramillustrating a circuit configuration of the magnetic field detectiondevice 10. The magnetic field detection device 10 may be used as acurrent sensor that detects, with high accuracy, a value of a currentflowing inside various electronic apparatuses, for example.

The magnetic field detection device 10 may include a bus 5 stacked inorder in a Z-axis direction, magnetic field detection elements 1 to 4,and a plurality of feedback wiring lines 6. The magnetic field detectionelement 1 and the magnetic field detection element 3 are each a specificbut non-limiting example corresponding to a “first magnetic fielddetection element” in one embodiment of the disclosure. The magneticfield detection element 2 and the magnetic field detection element 4 areeach a specific but non-limiting example corresponding to a “secondmagnetic field detection element” in one embodiment of the disclosure.

[Bus 5]

The bus 5 may be a conductor extending in a Y-axis direction, forexample, and may be supplied with a signal current Is to be detected bythe magnetic field detection device 10. A main constituent material ofthe bus 5 may be, for example, a high electrically-conductive materialsuch as copper (Cu). It may also be possible to use, as the constituentmaterial of the bus 5, an alloy containing iron (Fe) or nickel (Ni), orstainless steel. A signal current Is1 may flow in a +Y direction, forexample, inside the bus 5 to thereby enable generation of a signalmagnetic field Hs1 around the bus 5. Further, a signal current Is2 mayflow in a −Y direction inside the bus 5 to thereby enable generation ofa signal magnetic field Hs2 around the bus 5. The signal magnetic fieldHs1 may be applied to the magnetic field detection elements 1 to 4 in a+X direction. Meanwhile, the signal magnetic field Hs2 may be applied tothe magnetic field detection elements 1 to 4 in a −X direction.

The bus 5 is a specific but non-limiting example corresponding to a“first conductor” in one embodiment of the disclosure. The +Y directionis a specific but non-limiting example corresponding to a “first currentdirection” in one embodiment of the disclosure. The signal current Is1is a specific but non-limiting example corresponding to a “first signalcurrent” in one embodiment of the disclosure. The signal magnetic fieldHs1 is a specific but non-limiting example corresponding to a “firstmagnetic field” in one embodiment of the disclosure. The −Y direction isa specific but non-limiting example corresponding to a “second currentdirection” in one embodiment of the disclosure. The signal current Is2is a specific but non-limiting example corresponding to a “second signalcurrent” in one embodiment of the disclosure. The signal magnetic fieldHs2 is a specific but non-limiting example corresponding to a “secondmagnetic field” in one embodiment of the disclosure. Directions in whichthe signal current Is1 and the signal current Is2 flow are orthogonal todirections in which the signal magnetic field Hs1 and the signalmagnetic field Hs2 are applied to the magnetic field detection elements1 to 4.

[Feedback Wiring Line 6]

The plurality of feedback wiring lines 6 may be disposed to face each ofthe magnetic field detection elements 1 to 4 while being electricallyinsulated from each of the magnetic field detection elements 1 to 4. Theplurality of feedback wiring lines 6 may extend in the Y-axis directionalong the bus 5. Similarly to the bus 5, a main constituent material ofthe feedback wiring line 6 may be, for example, a highelectrically-conductive material such as copper (Cu). A feedback currentIf1 may flow in the +Y direction, for example, inside the feedbackwiring lines 6 to thereby enable generation of a feedback magnetic fieldHf1 around the feedback wiring lines 6. Further, a feedback current If2may flow in the −Y direction inside the feedback wiring lines 6 tothereby enable generation of a feedback magnetic field Hf2 around thefeedback wiring lines 6. The feedback magnetic field Hf1 may be appliedto the magnetic field detection elements 1 to 4 in the −X direction.Meanwhile, the feedback magnetic field Hf2 may be applied to themagnetic field detection elements 1 to 4 in the +X direction. That is,the feedback magnetic field Hf1 may be applied in a direction oppositeto the signal magnetic field Hs1 as viewed from the magnetic fielddetection elements 1 to 4, and the feedback magnetic field Hf2 may beapplied in a direction opposite to the signal magnetic field Hs2 asviewed from the magnetic field detection elements 1 to 4. Although thepresent example embodiment exemplifies five feedback wiring lines 6 thatare arranged in an X-axis direction, the number of the feedback wiringlines 6 is not limited thereto; only one feedback wiring line may beadopted.

The feedback wiring line 6 is a specific but non-limiting examplecorresponding to a “second conductor” in one embodiment of thedisclosure. The feedback current If1 is a specific but non-limitingexample corresponding to a “first feedback current” in one embodiment ofthe disclosure. The feedback current If2 is a specific but non-limitingexample corresponding to a “second feedback current” in one embodimentof the disclosure. The feedback magnetic field Hf1 is a specific butnon-limiting example corresponding to a “first feedback magnetic field”in one embodiment of the disclosure. The feedback magnetic field Hf2 isa specific but non-limiting example corresponding to a “second feedbackmagnetic field” in one embodiment of the disclosure.

[Magnetic Field Detection Elements 1 to 4]

The magnetic field detection elements 1 and 3 as the first magneticfield detection element each have a resistance value that increases uponapplication of the signal magnetic field Hs1 in the +X direction anddecreases upon application of the signal magnetic field Hs2 in the −Xdirection. Meanwhile, the magnetic field detection elements 2 and 4 asthe second magnetic field detection element each have a resistance valuethat decreases upon application of the signal magnetic field Hs1 in the+X direction and increases upon application of the signal magnetic fieldHs2 in the −X direction.

As illustrated in FIG. 2A, the magnetic field detection elements 1 and 3each include one or more magneto-resistive effect films MR1 and one ormore magneto-resistive effect films MR2. The one or moremagneto-resistive effect films MR1 and the one or more magneto-resistiveeffect films MR2 are coupled in series. The one or moremagneto-resistive effect films MR1 each have a major-axis direction J1inclined at an inclination angle θ1 relative to the +X direction. Theone or more magneto-resistive effect films MR2 each have a major-axisdirection J2 inclined at an inclination angle θ2 relative to the +Xdirection. Although FIG. 2A exemplifies two magneto-resistive effectfilms MR1 and two magneto-resistive effect films MR2 arrangedalternately along the Y-axis direction in the magnetic field detectionelements 1 and 3, the disclosure is not limited thereto. That is, themagnetic field detection elements 1 and 3 may be each provided with onemagneto-resistive effect film MR1 and one magneto-resistive effect filmMR2, or may be each provided with three or more magneto-resistive effectfilms MR1 and three or more magneto-resistive effect films MR2. Further,for example, the number of the magneto-resistive effect films MR1included in the magnetic field detection element 1 and the number of themagneto-resistive effect films MR2 included therein may be equal to ordifferent from each other; provided that a difference between the numberof the magneto-resistive effect films MR1 and the number of themagneto-resistive effect films MR2 may be within 20% or lower. In themagnetic field detection element 1, the sum of the number of themagneto-resistive effect films MR1 and the number of themagneto-resistive effect films MR2 may be an even number or an oddnumber. Accordingly, in the magnetic field detection element 1, forexample, the number of the magneto-resistive effect films MR1 may beeight, while the number of the magneto-resistive effect films MR2 may beten. In an alternative embodiment, the number of the magneto-resistiveeffect films MR1 may be nine, while the number of the magneto-resistiveeffect films MR2 may be eight. The similar to the magnetic fielddetection element 1 holds true also for the magnetic field detectionelement 3.

The magneto-resistive effect film MR1 is a specific but non-limitingexample corresponding to a “first magneto-resistive effect film” in oneembodiment of the disclosure. The magneto-resistive effect film MR2 is aspecific but non-limiting example corresponding to a “secondmagneto-resistive effect film” in one embodiment of the disclosure.

Moreover, the magneto-resistive effect film MR1 and themagneto-resistive effect film MR2 in each of the magnetic fielddetection elements 1 and 3 satisfy the following conditional expressions(1) and (2):0°<θ1<90°  (1)−90°<θ2<0°  (2)

where θ1 denotes an inclination angle of the major-axis direction J1relative to the +X direction, and θ2 denotes an inclination angle of themajor-axis direction J2 relative to the +X direction In the conditionalexpressions (1) and (2), the +X direction is set to 0°; an angle rangeclockwise from the +X direction toward the −X direction is representedby a positive numerical value, whereas an angle range counterclockwisefrom the +X direction toward the −X direction is represented by anegative numerical value.

In an example embodiment, the magneto-resistive effect film MR1 and themagneto-resistive effect film MR2 in each of the magnetic fielddetection elements 1 and 3 may further satisfy the following conditionalexpressions (3) and (4):50°<θ1<72°  (3)−72°<θ2<−50°  (4).In the conditional expressions (3) and (4) as well, the +X direction isset to 0°; an angle range clockwise from the +X direction toward the −Xdirection is represented by a positive numerical value, whereas an anglerange counterclockwise from the +X direction toward the −X direction isrepresented by a negative numerical value.

Satisfying θ1<72° in the conditional expression (3) or satisfying−72°<θ2 in the conditional expression (4) makes it possible to reverse amagnetization JS13, for example, described later of a magnetization freelayer S13, for example, described later in a ±Y direction, using arelatively small reversed magnetic field equal to or less than 30 mT,for example, as illustrated in FIG. 3A. Accordingly, it is possible toreduce the signal currents Is1 and Is2, which is preferable. FIG. 3A isa characteristic diagram illustrating a relation between the inclinationangle θ1 [°] indicated by a horizontal axis and the reversed magneticfield [mT] indicated by a vertical axis. The reversed magnetic field[mT] refers to a magnetic field where reversal of the magnetization JS13of the magnetization free layer S13 occurs. The characteristic diagramsof FIGS. 3A and 3B each illustrate an example of a magneto-resistiveeffect film MR with an elliptical planar shape having a dimension in amajor-axis direction of 5 μm and a dimension in a minor-axis directionof 0.6 μm. In this example, a state of the major axis being parallel tothe X-axis is represented by an equation of the inclination angle θ1=0°.The planar shape of the magneto-resistive effect film MR is not limitedto an ellipse; a rectangle, a rhombus, or a shape in which a rectangleand a rhombus are superposed on each other may be adopted. In an exampleembodiment, a ratio between the minor axis and the major axis, i.e., anaspect ratio having an influence on the reversed magnetic field may bein a range from 4 to 20. One reason for this is that magnetismhysteresis may occur to an external magnetic field, i.e., the signalmagnetic field Hs1 and the signal magnetic field Hs2 in the X-axisdirection when the aspect ratio is less than 4. Another reason for thisis that a reversed magnetic field necessary for the reversal of themagnetization JS13, for example, of the magnetization free layer S13,for example, may exceed 30 mT when the aspect ratio exceeds 20.

Moreover, satisfying 50°<θ1 in the conditional expression (3) orsatisfying θ2<−50° in the conditional expression (4) makes it possible,for example, to suppress output decline within 20% or lower as well assuppress an output variation, as illustrated in FIG. 3B. This makes itpossible to maintain favorable sensitivity for the signal magneticfields Hs1 and Hs2. FIG. 3B is a characteristic diagram illustrating arelation between the inclination angle θ1 [°] indicated by a horizontalaxis and an output variation [−] relative to a signal magnetic fieldindicated by a vertical axis. The output variation in the vertical axisis represented by a numerical value standardized with a maximum valueset as 100.

Likewise, as illustrated in FIG. 2B, the magnetic field detectionelements 2 and 4 each include a magneto-resistive effect film MR3 and amagneto-resistive effect film MR4 that are coupled in series. Themagneto-resistive effect film MR3 has a major-axis direction J3 inclinedat an inclination angle θ3 relative to the +X direction. Themagneto-resistive effect film MR4 has a major-axis direction J4 inclinedat an inclination angle θ4 relative to the +X direction. Although FIG.2B exemplifies two magneto-resistive effect films MR3 and twomagneto-resistive effect films MR4 arranged alternately along the Y-axisdirection in the magnetic field detection elements 2 and 4, thedisclosure is not limited thereto. That is, the magnetic field detectionelements 2 and 4 may be each provided with one magneto-resistive effectfilm MR3 and one magneto-resistive effect film MR4, or may be eachprovided with three or more magneto-resistive effect films MR3 and threeor more magneto-resistive effect films MR4. Further, for example, thenumber of the magneto-resistive effect films MR3 included in themagnetic field detection element 2 and the number of themagneto-resistive effect films MR4 included therein may be equal to ordifferent from each other; provided that a difference between the numberof the magneto-resistive effect films MR3 and the number of themagneto-resistive effect films MR4 may be within 20% or lower. In themagnetic field detection element 2, the sum of the number of themagneto-resistive effect films MR3 and the number of themagneto-resistive effect films MR4 may be an even number or an oddnumber. Accordingly, in the magnetic field detection element 2, forexample, the number of the magneto-resistive effect films MR3 may beeight, while the number of the magneto-resistive effect films MR4 may beten. In an alternative embodiment, the number of the magneto-resistiveeffect films MR3 may be nine, while the number of the magneto-resistiveeffect films MR4 may be eight. The similar to the magnetic fielddetection element 2 holds true also for the magnetic field detectionelement 4.

The magneto-resistive effect film MR3 is a specific but non-limitingexample corresponding to the “first magneto-resistive effect film” inone embodiment of the disclosure. The magneto-resistive effect film MR4is a specific but non-limiting example corresponding to the “secondmagneto-resistive effect film” in one embodiment of the disclosure.

Moreover, the magneto-resistive effect film MR3 and themagneto-resistive effect film MR4 in each of the magnetic fielddetection elements 2 and 4 satisfy the following conditional expressions(5) and (6):0°<θ3<90°  (5)−90°<θ4<0°  (6)

where θ3 denotes an inclination angle of the major-axis direction J3relative to the +X direction, and θ4 denotes an inclination angle of themajor-axis direction J4 relative to the +X direction In the conditionalexpressions (5) and (6) as well, the +X direction is set to 0°; an anglerange clockwise from the +X direction toward the −X direction isrepresented by a positive numerical value, whereas an angle rangecounterclockwise from the +X direction toward the −X direction isrepresented by a negative numerical value.

In an example embodiment, the magneto-resistive effect film MR3 and themagneto-resistive effect film MR4 in each of the magnetic fielddetection elements 2 and 4 may further satisfy the following conditionalexpressions (7) and (8):50°<θ3<72°  (7)−72°<θ4<−50°  (8).In the conditional expressions (7) and (8) as well, the +X direction isset to 0°; an angle range clockwise from the +X direction toward the −Xdirection is represented by a positive numerical value, whereas an anglerange counterclockwise from the +X direction toward the −X direction isrepresented by a negative numerical value.

FIG. 5A is an exploded perspective view of a stacked structure of themagneto-resistive effect film MR1 included in each of the magnetic fielddetection elements 1 and 3. FIG. 5B is an exploded perspective view of astacked structure of the magneto-resistive effect film MR2 included ineach of the magnetic field detection elements 1 and 3. FIG. 5C is anexploded perspective view of a stacked structure of themagneto-resistive effect film MR3 included in each of the magnetic fielddetection elements 2 and 4. FIG. 5D is an exploded perspective view of astacked structure of the magneto-resistive effect film MR4 included ineach of the magnetic field detection elements 2 and 4.

The magneto-resistive effect films MR1 to MR4 may each have a spin-valvestructure in which a plurality of functional films including a magneticlayer are stacked, as illustrated in FIGS. 5A to 5D. In a specific butnon-limiting example, as illustrated in FIG. 5A, the magneto-resistiveeffect film MR1 may have a configuration in which a magnetization pinnedlayer S11, an intermediate layer S12, and the magnetization free layerS13 are stacked in order in the Z-axis direction. The magnetizationpinned layer S11 may have a magnetization JS11 pinned in the +Xdirection. The intermediate layer S12 may be a non-magnetic body. Themagnetization free layer S13 may have the magnetization JS13 that variesdepending on magnetic flux density of each of the signal magnetic fieldsHs1 and Hs2. The magnetization pinned layer S11, the intermediate layerS12, and the magnetization free layer S13 may be each a thin film thatextends in an X-Y plane. Accordingly, an orientation of themagnetization JS13 of the magnetization free layer S13 may be rotatablein the X-Y plane.

As illustrated in FIG. 5B, the magneto-resistive effect film MR2 mayhave a configuration in which a magnetization pinned layer S21, anintermediate layer S22, and a magnetization free layer S23 are stackedin order in the Z-axis direction. The magnetization pinned layer S21 mayhave a magnetization JS21 pinned in the +X direction. The intermediatelayer S22 may be a non-magnetic body. The magnetization free layer S23may have a magnetization JS23 that varies depending on the magnetic fluxdensity of each of the signal magnetic fields Hs1 and Hs2. Themagnetization pinned layer S21, the intermediate layer S22, and themagnetization free layer S23 may be each a thin film that extends in theX-Y plane. Accordingly, an orientation of the magnetization JS23 of themagnetization free layer S23 may be rotatable in the X-Y plane.

As illustrated in FIG. 5C, the magneto-resistive effect film MR3 mayhave a configuration in which a magnetization pinned layer S31, anintermediate layer S32, and a magnetization free layer S33 are stackedin order in the Z-axis direction. The magnetization pinned layer S31 mayhave a magnetization JS31 pinned in the −X direction. The intermediatelayer S32 may be a non-magnetic body. The magnetization free layer S33may have a magnetization JS33 that varies depending on the magnetic fluxdensity of each of the signal magnetic fields Hs1 and Hs2. Themagnetization pinned layer S31, the intermediate layer S32, and themagnetization free layer S33 may be each a thin film that extends in theX-Y plane. Accordingly, an orientation of the magnetization JS33 of themagnetization free layer S33 may be rotatable in the X-Y plane.

As illustrated in FIG. 5D, the magneto-resistive effect film MR4 mayhave a configuration in which a magnetization pinned layer S41, anintermediate layer S42, and a magnetization free layer S43 are stackedin order in the Z-axis direction. The magnetization pinned layer S41 mayhave a magnetization JS41 pinned in the −X direction. The intermediatelayer S42 may be a non-magnetic body. The magnetization free layer S43may have a magnetization JS43 that varies depending on the magnetic fluxdensity of each of the signal magnetic fields Hs1 and Hs2. Themagnetization pinned layer S41, the intermediate layer S42, and themagnetization free layer S43 may be each a thin film that extends in theX-Y plane. Accordingly, an orientation of the magnetization JS43 of themagnetization free layer S43 may be rotatable in the X-Y plane.

As described, the magnetization pinned layers S11 and S21 in therespective magneto-resistive effect films MR1 and MR2 may have themagnetizations JS11 and JS21, respectively, both pinned in the +Xdirection. Meanwhile, the magnetization pinned layers S31 and S41 in therespective magneto-resistive effect films MR3 and MR4 may have themagnetizations JS31 and JS41, respectively, both pinned in the −Xdirection.

The magnetizations JS11 and JS21 are each a specific but non-limitingexample corresponding to a “first magnetization” in one embodiment ofthe disclosure. The magnetization pinned layers S11 and S21 are each aspecific but non-limiting example corresponding to a “firstmagnetization pinned layer” in one embodiment of the disclosure. Themagnetizations JS31 and JS41 are each a specific but non-limitingexample corresponding to a “second magnetization” in one embodiment ofthe disclosure. The magnetization pinned layers S31 and S41 are each aspecific but non-limiting example corresponding to a “secondmagnetization pinned layer” in one embodiment of the disclosure.

In the magneto-resistive effect films MR1 to MR4, the magnetizationpinned layers S11, S21, S31, and S41, the intermediate layers S12, S22,S32, and S42, and the magnetization free layers S13, S23, S33, and S43may each have a single-layer structure or a multi-layer structureconfigured by a plurality of layers. For example, in themagneto-resistive effect films MR1 to MR4, the magnetization pinnedlayers S11, S21, S31, and S41 may each have a stacked ferrimagneticstructure, as illustrated in FIGS. 6A to 6D. In a specific butnon-limiting example, as illustrated in FIG. 6A, the magnetizationpinned layer S11 of the magneto-resistive effect film MR1 may have atwo-layer structure including a magnetization pinned film S11A having amagnetization JS11A and a magnetization pinned film S11B havingmagnetization JS11B. An orientation of the magnetization JS11A and anorientation of the magnetization JS11B may be opposite to each other. Ina specific but non-limiting example, the magnetization JS11A may bepinned in the +X direction, and the magnetization JS11B may be pinned inthe −X direction. Likewise, as illustrated in FIG. 6B, the magnetizationpinned layer S21 of the magneto-resistive effect film MR1 may have atwo-layer structure including a magnetization pinned film S21A having amagnetization JS21A and a magnetization pinned film S21B having amagnetization JS21B. An orientation of the magnetization JS21A and anorientation of the magnetization JS21B may be opposite to each other. Ina specific but non-limiting example, the magnetization JS21A may bepinned in the +X direction, and the magnetization JS21B may be pinned inthe −X direction. As illustrated in FIG. 6C, the magnetization pinnedlayer S31 of the magneto-resistive effect film MR3 may have a two-layerstructure including a magnetization pinned film S31A having amagnetization JS31A and a magnetization pinned film S31B having amagnetization JS31B. An orientation of the magnetization JS31A and anorientation of the magnetization JS31B may be opposite to each other. Ina specific but non-limiting example, the magnetization JS31A may bepinned in the −X direction, and the magnetization JS31B may be pinned inthe +X direction. As illustrated in FIG. 6D, the magnetization pinnedlayer S41 of the magneto-resistive effect film MR4 may have a two-layerstructure including a magnetization pinned film S41A having amagnetization JS41A and a magnetization pinned film S41B having amagnetization JS41B. An orientation of the magnetization JS41A and anorientation of the magnetization JS41B may be opposite to each other. Ina specific but non-limiting example, the magnetization JS41A may bepinned in the −X direction, and the magnetization JS41B may be pinned inthe +X direction.

The magnetization pinned layers S11, S21, S31, and S41 may each include,for example, a ferromagnetic material such as cobalt (Co), a cobalt-ironalloy (CoFe), and a cobalt-iron-boron alloy (CoFeB). In themagneto-resistive effect films MR1 to MR4, unillustratedantiferromagnetic layers may be provided on sides opposite to therespective intermediate layers S12, S22, S32, and S42 to allow theantiferromagnetic layers to be adjacent to the respective magnetizationpinned layers S11, S21, S31, and S41. Such antiferromagnetic layers maybe each configured by an antiferromagnetic material such as aplatinum-manganese alloy (PtMn) and an iridium-manganese alloy (IrMn).In the magneto-resistive effect films MR1 to MR4, the antiferromagneticlayers may be each in a state in which a spin magnetic moment in the +Xdirection and a spin magnetic moment in the −X direction completelycancel each other. The antiferromagnetic layers may serve to fixorientations of the respective magnetizations JS11 and JS21 of theadjacent magnetization pinned layers S11 and S21 to the +X direction, orto fix orientations of the respective magnetizations JS31 and JS41 ofthe adjacent magnetization pinned layers S31 and S41 to the −Xdirection.

In a case where the spin valve structure serves as a magnetic tunneljunction (MTJ) film, the intermediate layers S12, S22, S32, and S42 maybe each a non-magnetic tunnel barrier layer including magnesium oxide(MgO), for example, and may be each thin enough to enable a tunnelcurrent based on quantum mechanics to pass therethrough. The tunnelbarrier layer including MgO may be obtained by a process such as aprocess of oxidizing a thin film including magnesium (Mg) and a reactivesputtering process in which sputtering of magnesium is performed underan oxygen atmosphere, besides a sputtering process that uses a targetincluding MgO, for example. It may also be possible to configure each ofthe intermediate layers S12, S22, S32, and S42 with use of an oxide or anitride of each of aluminum (Al), tantalum (Ta), and hafnium (Hf),besides MgO. The intermediate layers S12, S22, S32, and S42 may be eachconfigured by a platinum group element such as ruthenium (Ru), or anon-magnetic metal such as gold (Au) and copper (Cu), for example. Insuch a case, the spin valve structure may serve as a giantmagneto-resistive effect (GMR) film.

The magnetization free layers S13, S23, S33, and S43 may be each a softferromagnetic layer, and may be formed by substantially the samematerial as each other. The magnetization free layers S13, S23, S33, andS43 may be each configured by, for example, a material such as acobalt-iron alloy (CoFe), a nickel-iron alloy (NiFe), and acobalt-iron-boron alloy (CoFeB).

[Bridge Circuit 7]

As illustrated in FIG. 4 , four magnetic field detection elements 1 to 4may be bridged to form a bridge circuit 7. The magnetic field detectionelements 1 to 4 may be able to detect a variation in the signal magneticfield Hs1 or signal magnetic field Hs2 to be detected. As describedabove, the magnetic field detection elements 1 and 3 each have aresistance value that increases upon application of the signal magneticfield Hs1 in the +X direction and decreases upon application of thesignal magnetic field Hs2 in the −X direction. Meanwhile, the magneticfield detection elements 2 and 4 each have a resistance value thatdecreases upon application of the signal magnetic field Hs1 in the +Xdirection and increases upon application of the signal magnetic fieldHs2 in the −X direction. Accordingly, the magnetic field detectionelements 1 and 3 and the magnetic field detection elements 2 and 4 mayoutput respective signals depending on the variation in the signalmagnetic field Hs1 or the signal magnetic field Hs2. Phases of therespective signals may be different from each other by 180°, forexample.

As illustrated in FIG. 4 , the bridge circuit 7 may have a configurationin which the magnetic field detection element 1 and the magnetic fielddetection element 2 coupled in series and the magnetic field detectionelement 3 and the magnetic field detection element 4 coupled in seriesare coupled in parallel to each other. In a more specific butnon-limiting example, in the bridge circuit 7, one end of the magneticfield detection element 1 and one end of the magnetic field detectionelement 2 may be coupled at a node P1; one end of the magnetic fielddetection element 3 and one end of the magnetic field detection element4 may be coupled at a node P2; the other end of the magnetic fielddetection element 1 and the other end of the magnetic field detectionelement 4 may be coupled at a node P3; and the other end of the magneticfield detection element 2 and the other end of the magnetic fielddetection element 3 may be coupled at a node P4. The node P3 may becoupled to a power supply terminal Vcc, and the node P4 may be coupledto a ground terminal GND. The node P1 may be coupled to an outputterminal Vout1, and the node P2 may be coupled to an output terminalVout2. Each of the output terminal Vout1 and the output terminal Vout2may be coupled to an input-side terminal of a differential detector 8,for example. This differential detector 8 may detect a potentialdifference between the node P1 and the node P2 at a time when a voltageis applied between the node P3 and the node P4, and output the detectedpotential difference to an arithmetic circuit 9 as a differential signalS. The potential difference between the node P1 and the node P2 may be adifference between voltage drops that are respectively generated in themagnetic field detection element 1 and the magnetic field detectionelement 4.

In FIG. 4 , an arrow with reference numerals JS11 and JS21 schematicallyindicates orientations of the magnetizations JS11 and JS21, illustratedrespectively in FIGS. 5A and 5B, of the magnetization pinned layers S11and S21, illustrated respectively in FIGS. 5A and 5B, in each of themagnetic field detection elements 1 and 3. Further, in FIG. 4 , an arrowwith reference numerals JS31 and JS41 schematically indicatesorientations of the magnetizations JS31 and JS41, illustratedrespectively in FIGS. 5C and 5D, of the magnetization pinned layers S31and S41, illustrated respectively in FIGS. 5C and 5D, in each of themagnetic field detection elements 2 and 4. As illustrated in FIG. 4 ,the orientation of the magnetizations JS11 and JS21 and the orientationof the magnetizations JS31 and JS41 may be opposite to each other. Inother words, FIG. 4 illustrates that a resistance value of the magneticfield detection element 1 and a resistance value of the magnetic fielddetection element 3 vary, e.g., increase or decrease in the sameorientation as each other depending on the variation in the signalmagnetic field Hs1 or Hs2. FIG. 4 also illustrates that both aresistance value of the magnetic field detection element 2 and aresistance value of the magnetic field detection element 4 vary, i.e.,decrease or increase in an orientation opposite to those of thevariations in the respective resistance values of the magnetic fielddetection elements 1 and 3 depending on the variation in the signalmagnetic field Hs1 or Hs2.

Current I10 from the power supply terminal Vcc may split into a currentI1 and a current I2 at the node P3. The current I1 or the current I2 maybe supplied to each of the magnetic field detection elements 1 to 4constituting the bridge circuit 7. Signals e1 and e2 may respectively beextracted from the nodes P2 and P1 of the bridge circuit 7. The signalse1 and e2 may flow into the differential detector 8.

[Operations and Workings of Magnetic Field Detection Device 10]

In the magnetic field detection device 10 according to the presentembodiment, it is possible to detect variations in the signal magneticfields Hs1 and Hs2 generated, respectively, by the signal currents Is1and Is2 flowing through the bus 5.

[Detecting Operation]

First, consider a state where neither the signal magnetic field Hs1 northe signal magnetic field Hs2 is applied, in the magnetic fielddetection device 10. Here, r1 to r4 are set that denote respectiveresistance values of the magnetic field detection elements 1 to 4 at atime when the current I10 is flowed to the bridge circuit 7. The currentI10 from the power supply terminal Vcc may split into two currents ofthe current I1 and the current I2 at the node P3. Thereafter, thecurrent I1 having passed through the magnetic field detection element 1and the magnetic field detection element 2 and the current I2 havingpassed through the magnetic field detection element 4 and the magneticfield detection element 3 may join at the node P4. In this case, apotential difference V between the node P3 and the node P4 may berepresented as follows.V=I1*r1+I1*r2=I2*r4+I2*r3=I1*(r1+r2)=I2*(r4+r3)  (9)Further, a potential V1 at the node P1 and a potential V2 at the node P2may be represented as follows.V1=V−I1*r1V2=V−I2*r4Accordingly, a potential difference V0 between the node P1 and the nodeP2 is as follows.V0=V2−V1=(V−I2*r4)−(V−I1*r1)=I1*r1−I2*r4  (10)Here, from the expression (9), the following expression holds true.V0=r1/(r1+r2)×V−r4/(r4+r3)×V={r1/(r1+r2)−r4/(r4+r3)}×V  (11)In the bridge circuit 7, the potential difference V0 between the node P2and the node P1 represented by the above expression (11) may be measuredwhen the signal magnetic fields Hs1 and Hs2 are applied, therebyallowing for obtainment of an amount of a resistance variation. Here,suppose that resistance values R1 to R4 of the respective magnetic fielddetection elements 1 to 4 vary by respective variation amounts AR1 toAR4 when the signal magnetic fields Hs1 and Hs2 are applied, i.e.,suppose that the resistance values R1 to R4 after application of thesignal magnetic fields Hs1 and Hs2 satisfy the following expressions.R1=r1+ΔR1R2=r2+ΔR2R3=r3+ΔR3R4=r4+ΔR4In that case, from the expression (11), the potential difference V0 uponthe application of the signal magnetic fields Hs1 and Hs2 is as follows.V0={(r1+ΔR1)/(r1+ΔR1+r2+ΔR2)−(r4+ΔR4)/(r4+ΔR4+r3+ΔR3)}×V   (12)The magnetic field detection device 10 may have a configuration in whichthe respective resistance values R1 and R3 of the magnetic fielddetection elements 1 and 3 and the respective resistance values R2 andR4 of the magnetic field detection elements 2 and 4 exhibit variationsin directions opposite to each other. Accordingly, it follows that thevariation amount ΔR4 and the variation amount ΔR1 cancel each other andthat the variation amount ΔR3 and the variation amount ΔR2 cancel eachother. Hence, in a case where comparison is made between before andafter the application of the signal magnetic fields Hs1 and Hs2, thereis substantially no increase in denominators of respective terms of theexpression (12). Meanwhile, in numerators of the respective terms, itfollows that an increase or a decrease appears because of the variationamount ΔR1 and the variation amount ΔR4 always having opposite signs.

Suppose that all of the magnetic field detection elements 1 to 4 haveexactly the same characteristics, i.e., suppose that r1=r2=r3=r4 andΔR1=−ΔR2=ΔR3=−ΔR4=ΔR hold true, the expression (12) is as follows.V0={(R+ΔR)/(2×R)−(R−ΔR)/(2×R)}×V=(ΔR/R)×V

As described, by using the magnetic field detection elements 1 to 4 thatare known in terms of characteristic values such as ΔR/R, it becomespossible to measure magnitude of the signal magnetic fields Hs1 and Hs2and thus to estimate magnitude of the signal currents Is1 and Is2 thatgenerate, respectively, the signal magnetic fields Hs1 and Hs2.

[Set-Reset Operation]

In a magnetic field detection device of this kind, magnetizations ofmagnetization free layers in each of magnetic field detection elementsmay be once aligned in a predetermined direction before performing adetecting operation of a signal magnetic field, in an exampleembodiment. One reason for this is to perform more accurate detectingoperation of a signal magnetic field. In a specific but non-limitingexample, an external magnetic field having known magnitude may beapplied alternately in a predetermined direction and in a directionopposite thereto. This operation is referred to as a set-reset operationof a magnetization of a magnetization free layer.

In the magnetic field detection device 10 of the present exampleembodiment, for example, the feedback current If1 in the +Y directionmay be supplied to each of the plurality of feedback wiring lines 6 toperform the set operation, as illustrated in FIGS. 7A and 7B. The supplyof the feedback current If1 in the +Y direction enables the feedbackmagnetic field Hf1 in the −X direction to be applied to themagneto-resistive effect films MR1 to MR4 of each of the magnetic fielddetection elements 1 to 4, as illustrated in FIG. 7B. This causes themagnetization free layers S13, S23, S33, and S43 of the respectivemagneto-resistive effect films MR1 to MR4 to be oriented in respectivearrow directions indicated in FIG. 7A, thus performing the setoperation. Meanwhile, for example, the feedback current If2 in the −Ydirection may be supplied to each of the plurality of feedback wiringlines 6 to perform the reset operation, as illustrated in FIGS. 8A and8B. The supply of the feedback current If2 in the −Y direction enablesthe feedback magnetic field Hf2 in the +X direction to be applied to themagneto-resistive effect films MR1 to MR4 of each of the magnetic fielddetection elements 1 to 4, as illustrated in FIG. 8B. This causes themagnetization free layers S13, S23, S33, and S43 of the respectivemagneto-resistive effect films MR1 to MR4 to be oriented in respectivearrow directions indicated in FIG. 8A, thus performing the resetoperation.

It is originally desirable, at an ordinary temperature, for example, toset an output from each of the magnetic field detection elements to zerowhen an external magnetic field is zero. Actually, however, a slightoutput may occur from each of the magnetic field detection elements evenwhen the external magnetic field is zero, due to history of amagnetization in the magnetization free layer. The slight output isreferred to as an offset value. For example, external factors may causereversal of the orientation of the magnetization of the magnetizationfree layer in some cases, resulting in occurrence of variation in theoffset value in some cases. Non-limiting examples of the externalfactors may include humidity, heat, variation in stress, and adisturbance magnetic field in a major-axis direction to be imparted tothe magneto-resistive effect films MR1 to MR. The set operation and thereset operation on the magnetization free layer may be each a methodthat makes it possible to return an offset value, having been variedunintentionally due to the above-mentioned external factors, to anoriginal offset value effectively and with high reproducibility. Anabsolute value of the offset value after the set operation and anabsolute value of the offset value after the reset operation may be eachas small as possible, in an example embodiment.

In this respect, it is possible for the magnetic field detection device10 of the present example embodiment to sufficiently reduce a gapbetween the offset value after the set operation and the offset valueafter the reset operation. Reasons for this are that the magnetic fielddetection elements 1 and 3 may each include the magneto-resistive effectfilm MR1 and the magneto-resistive effect film MR2 and that the magneticfield detection elements 2 and 4 may each include the magneto-resistiveeffect film MR3 and the magneto-resistive effect film MR4. Themagneto-resistive effect film MR1 may have the major-axis direction J1that forms the inclination angle θ1 relative to the signal magneticfields Hs1 and Hs2. The magneto-resistive effect film MR2 may have themajor-axis direction J2 that forms the inclination angle θ2 relative tothe signal magnetic fields Hs1 and Hs2. The magneto-resistive effectfilm MR3 may have the major-axis direction J3 that forms the inclinationangle θ3 relative to the signal magnetic fields Hs1 and Hs2. Themagneto-resistive effect film MR4 may have the major-axis direction J4that forms the inclination angle θ4 relative to the signal magneticfields Hs1 and Hs2.

[Effects of Magnetic Field Detection Device 10]

As described, the magnetic field detection device 10 of the presentexample embodiment makes it possible to exhibit high detection accuracy.

Experimental Examples

Description is given next of a working example of the disclosure.

Working Example

Thirty-two samples were prepared for the magnetic field detection device10 illustrated in figures such as FIG. 1 . For each of the samples, anoffset value after the set operation described with reference to FIGS.7A and 7B and an offset value after the reset operation described withreference to FIGS. 8A and 8B were measured. The results of themeasurement are illustrated in FIG. 9A. In FIG. 9A, the horizontal axisindicates a sample number, and the vertical axis indicates an offsetvalue. The offset value after the set operation is indicated by a legend●, and the offset value after the reset operation is indicated by alegend Δ.

Reference Example

As a reference example to be used for comparison with the magnetic fielddetection device 10, thirty-two samples were prepared for a magneticfield detection device provided with only a magnetic field detectionelement including a plurality of magneto-resistive effect films MR1, asillustrated in FIG. 13 , having respective major-axis directionsinclined in the same direction relative to the signal magnetic fieldsHs1 and Hs2. For each of the samples, an offset value after the setoperation and an offset value after the reset operation were measured.The results of the measurement are illustrated in FIG. 9B. In FIG. 9B,the horizontal axis indicates a sample number, and the vertical axisindicates an offset value. The offset value after the set operation isindicated by a legend ●, and the offset value after the reset operationis indicated by a legend Δ.

It was confirmed, from comparison between FIGS. 9A and 9B, thatdispersion of offset values is obviously smaller in the working exampleillustrated in FIG. 9A than in the reference example illustrated in FIG.9B, both after the set operation and after the reset operation.

2. Modification Examples

The disclosure has been described hereinabove referring to someembodiments. However, the disclosure is not limited to such embodiments,and may be modified in a variety of ways. For example, in the foregoingembodiments, the four magnetic field detection elements are used as asensor section to form a full-bridge circuit. However, in one embodimentof the disclosure, for example, two magnetic field detection elementsmay be used to form a half-bridge circuit. Further, a shape and adimension of the plurality of magneto-resistive effect films may be thesame as one another, or may be different from one another. Dimensions ofrespective components and layouts of the respective components aremerely illustrative, and are not limited thereto.

The foregoing example embodiment exemplifies the case where theplurality of magneto-resistive effect films in each of the magneticfield detection elements 1 to 4 are arranged along the Y-axis directionthat is an extending direction of the bus 5 and the feedback wiringlines 6. However, the disclosure is not limited thereto. For example, asin a first modification example illustrated in FIG. 10A or in a secondmodification example illustrated in FIG. 10B, the plurality ofmagneto-resistive effect films may be arranged along the X-axisdirection to be parallel to the signal magnetic fields Hs1 and Hs2.

The foregoing example embodiment exemplifies the case where themagneto-resistive effect film MR1 (MR3) and the magneto-resistive effectfilm MR2 (MR4) are arranged alternately in each of the magnetic fielddetection elements 1 to 4. However, the disclosure is not limitedthereto. For example, as in a third modification example illustrated inFIG. 11 , the plurality of magneto-resistive effect films inclined inthe same orientation may be arranged to be adjacent to each other.

In the foregoing example embodiment, each of the orientations of themagnetizations JS11 and JS21 of the respective magnetization pinnedlayers S11 and S21 is set in the +X direction, and each of theorientations of the magnetizations JS31 and JS41 of the respectivemagnetization pinned layers S31 and S41 is set in the −X direction.However, the disclosure is not limited thereto. For example, as in afourth modification example illustrated in FIGS. 12A and 12B, theorientations of the magnetizations JS11, JS21, JS31, and JS41 may be setin directions orthogonal, respectively, to the major-axis directions J1to J4 of the magneto-resistive effect films MR1 to MR4.

The description has been given, in the foregoing example embodiment, ofthe case where the bus 5 as the first conductor and the feedback wiringlines 6 as the second conductor extend in parallel to each other.However, the disclosure is not limited thereto. For example, the secondconductor may be slightly inclined relative to the first conductor. Inthis case, it is sufficient that a feedback current flowing through thesecond conductor may generate a feedback magnetic field including acomponent in an orientation opposite to a signal magnetic fieldgenerated by a signal current flowing through the first conductor.

The description has been given, in the foregoing example embodiment, ofthe magnetic field detection device to be used as a current sensor thatdetects variation in a signal current flowing through a conductor.However, the application of the magnetic field detection device of anembodiment of the disclosure is not limited thereto. The magnetic fielddetection device of an embodiment of the disclosure is also applicable,for example, to a magnetic field detection device to be used as an angledetection sensor for use in detection of a rotation angle of a rotor, orto an electromagnetic compass that detects geomagnetism.

Moreover, the disclosure encompasses any possible combination of some orall of the various embodiments and the modification examples describedherein and incorporated herein.

It is possible to achieve at least the following configurations from theabove-described example embodiments of the disclosure.

(1)

A magnetic field detection device including:

a first magnetic field detection element having a first resistance valuethat increases upon application of a first magnetic field in a firstdirection and decreases upon application of a second magnetic field in asecond direction opposite to the first direction; and

a second magnetic field detection element having a second resistancevalue that decreases upon the application of the first magnetic fieldand increases upon the application of the second magnetic field,

the first magnetic field detection element and the second magnetic fielddetection element each including a first magneto-resistive effect filmand a second magneto-resistive effect film that are coupled in series,the first magneto-resistive effect film having a first major-axisdirection inclined at a first inclination angle relative to the firstdirection, the second magneto-resistive effect film having a secondmajor-axis direction inclined at a second inclination angle relative tothe first direction,

the following conditional expressions (1) and (2) being satisfied:0°<θ1<90°  (1)−90°<θ2<0°  (2)

where

θ1 denotes the first inclination angle of the first major-axis directionrelative to the first direction, and

θ2 denotes the second inclination angle of the second major-axisdirection relative to the first direction.

(2)

The magnetic field detection device according to (1), in which thefollowing conditional expressions (3) and (4) are satisfied:50°<θ1<72°  (3)−72°<θ2<−50°  (4).(3)

The magnetic field detection device according to (1) or (2), in which

the first magneto-resistive effect film includes a first magnetizationpinned layer having a magnetization pinned in a first pinning directionsubstantially orthogonal to the first major-axis direction, and

the second magneto-resistive effect film includes a second magnetizationpinned layer having a magnetization pinned in a second pinning directionsubstantially orthogonal to the second major-axis direction.

(4)

The magnetic field detection device according to (1) or (2), in which

the first magneto-resistive effect film includes a first magnetizationpinned layer having a first magnetization pinned in the first direction,and

the second magneto-resistive effect film includes a second magnetizationpinned layer having a second magnetization pinned in the seconddirection.

(5)

The magnetic field detection device according to any one of (1) to (4),further including a first conductor configured to generate the firstmagnetic field by a first signal current and to generate the secondmagnetic field by a second signal current, the first signal currentflowing in a first current direction orthogonal to both of the firstdirection and the second direction, the second signal current flowing ina second current direction opposite to the first current direction.

(6)

The magnetic field detection device according to any one of (1) to (4),further including a second conductor disposed to face both of the firstmagnetic field detection element and the second magnetic field detectionelement while being electrically insulated from both of the firstmagnetic field detection element and the second magnetic field detectionelement, in which

the second conductor is configured to generate a first feedback magneticfield in an orientation opposite to the first magnetic field by beingsupplied with a first feedback current, the first feedback magneticfield including a component to be imparted to both of the first magneticfield detection element and the second magnetic field detection element,and

the second conductor is configured to generate a second feedbackmagnetic field in an orientation opposite to the second magnetic fieldby being supplied with a second feedback current, the second feedbackmagnetic field including a component to be imparted to both of the firstmagnetic field detection element and the second magnetic field detectionelement.

(7)

The magnetic field detection device according to any one of (1) to (6),in which

the first magneto-resistive effect film includes a plurality of firstmagneto-resistive effect films,

the second magneto-resistive effect film includes a plurality of secondmagneto-resistive effect films,

the first magnetic field detection element and the second magnetic fielddetection element each include the plurality of first magneto-resistiveeffect films and the plurality of second magneto-resistive effect films,

the plurality of first magneto-resistive effect films are substantiallyequal in the first inclination angle of the first major-axis direction,and

the plurality of second magneto-resistive effect films are substantiallyequal in the second inclination angle of the second major-axisdirection.

According to the magnetic field detection device of one embodiment ofthe disclosure, it is possible to exhibit high detection accuracy.

Although the disclosure has been described in terms of exemplaryembodiments, it is not limited thereto. It should be appreciated thatvariations may be made in the described embodiments by persons skilledin the art without departing from the scope of the disclosure as definedby the following claims. The limitations in the claims are to beinterpreted broadly based on the language employed in the claims and notlimited to examples described in this specification or during theprosecution of the application, and the examples are to be construed asnon-exclusive. For example, in this disclosure, the term “preferably”,“preferred” or the like is non-exclusive and means “preferably”, but notlimited to. The use of the terms first, second, etc. do not denote anyorder or importance, but rather the terms first, second, etc. are usedto distinguish one element from another. The term “substantially” andits variations are defined as being largely but not necessarily whollywhat is specified as understood by one of ordinary skill in the art. Theterm “about” as used herein can allow for a degree of variability in avalue or range. Moreover, no element or component in this disclosure isintended to be dedicated to the public regardless of whether the elementor component is explicitly recited in the following claims.

What is claimed is:
 1. A magnetic field detection device comprising: afirst plurality of films having a first resistance value that increasesupon application of a first magnetic field in a first direction anddecreases upon application of a second magnetic field in a seconddirection opposite to the first direction; and a second plurality offilms, the first plurality of films and the second plurality of filmseach including a first magneto-resistive effect film and a secondmagneto-resistive effect film, the first magneto-resistive effect filmhaving a first major-axis direction inclined at a first inclinationangle relative to the first direction, the second magneto-resistiveeffect film having a second major-axis direction inclined at a secondinclination angle relative to the first direction, the followingconditional expressions (1) and (2) being satisfied:0°<θ1<90°  (1)−90°<θ2<0°  (2) where θ1 denotes the first inclination angle of thefirst major-axis direction relative to the first direction, and θ2denotes the second inclination angle of the second major-axis directionrelative to the first direction.
 2. The magnetic field detection deviceaccording to claim 1, wherein the first magneto-resistive effect filmand the second magneto-resistive effect film are coupled in series. 3.The magnetic field detection device according to claim 1, wherein thefollowing conditional expressions (3) and (4) are satisfied:50°<θ1<72°  (3)−72°<θ2<−50°  (4).
 4. The magnetic field detection device according toclaim 1, wherein the first magneto-resistive effect film includes afirst magnetization pinned layer having a magnetization pinned in afirst pinning direction substantially orthogonal to the first major-axisdirection, and the second magneto-resistive effect film includes asecond magnetization pinned layer having a magnetization pinned in asecond pinning direction substantially orthogonal to the secondmajor-axis direction.
 5. The magnetic field detection device accordingto claim 1, wherein the first magneto-resistive effect film and thesecond magneto-resistive effect film in the first plurality of filmseach include a first magnetization pinned layer having a firstmagnetization pinned in the first direction, and the firstmagneto-resistive effect film and the second magneto-resistive effectfilm in the second plurality of films each include a secondmagnetization pinned layer having a second magnetization pinned in thesecond direction.
 6. The magnetic field detection device according toclaim 1, further comprising a first conductor configured to generate thefirst magnetic field by a first signal current and to generate thesecond magnetic field by a second signal current, the first signalcurrent flowing in a first current direction orthogonal to both of thefirst direction and the second direction, the second signal currentflowing in a second current direction opposite to the first currentdirection.
 7. The magnetic field detection device according to claim 1,further comprising a second conductor disposed to face both of the firstplurality of films and the second plurality of films while beingelectrically insulated from both of the first plurality of films and thesecond plurality of films, wherein the second conductor is configured togenerate a first feedback magnetic field in an orientation opposite tothe first magnetic field by being supplied with a first feedbackcurrent, the first feedback magnetic field including a component to beimparted to both of the first plurality of films and the secondplurality of films, and the second conductor is configured to generate asecond feedback magnetic field in an orientation opposite to the secondmagnetic field by being supplied with a second feedback current, thesecond feedback magnetic field including a component to be imparted toboth of the first plurality of films and the second plurality of films.8. The magnetic field detection device according to claim 1, wherein thefirst magneto-resistive effect film comprises a plurality of firstmagneto-resistive effect films, the second magneto-resistive effect filmcomprises a plurality of second magneto-resistive effect films, thefirst plurality of films and the second plurality of films each includethe plurality of first magneto-resistive effect films and the pluralityof second magneto-resistive effect films, the plurality of firstmagneto-resistive effect films are substantially equal in the firstinclination angle of the first major-axis direction, and the pluralityof second magneto-resistive effect films are substantially equal in thesecond inclination angle of the second major-axis direction.